Floating switch with ssr expension board

I mounted a water level floating switch for HLT and BOIL kettle. With a brewpi ssr expension board I can switch the HLT with one of the wires from the expension board to the other ssr but can’t figure out how to switch the BOIL kettle. Do I have to disconnect the board form the ssr?

Just interrupt the control signal to the SSR with the switch.

You will have 2 wires going to the SSR. Let the switch interrupt one of them.